At The Spectator, I discuss last week's lowering of the sugar 'allowance'. Some people have said they can't access the site if they're using Chrome so here it is in full...
Like putting Dracula in charge of a blood bank’ is how Action on Sugar’s Simon Capewell described
Ian MacDonald’s role as chairman of the Scientific Advisory Committee
on Nutrition (SACN) last year. Professor MacDonald’s reputation as one
of Britain’s leading nutritionists gave him no protection when Channel
4’s Dispatches
programme devoted half an hour to attacking any scientist who receives
grant funding from the food industry. Seemingly unaware that
industry-government partnerships are the norm in diet research, Action
on Sugar’s Aseem Malhotra accused MacDonald of being ‘in bed with the
food industry’ and called for his resignation. Similar inferences and
accusations were made in a British Medical Journal ‘investigation’ earlier this year.
We shall probably never know whether this smear campaign had any influence on the conclusions of the SACN report when it was released last week, but the campaigners certainly got what they wanted when MacDonald et al
halved the recommended sugar intake from 10 per cent of daily calories
to five per cent. A lower limit has been the holy grail for the
anti-sugar movement for years (for reasons I recently discussed).
The World Health Organisation let them down earlier this year when it
kept the limit at ten per cent, but SACN played ball and the talk of
Dracula and blood banks was conspicuous by its absence on Friday
morning.
The pool of nutritional epidemiology is murky at the best of times, leading some academics to dismiss the whole field as pseudoscience,
but if you are prepared to give it the benefit of the doubt, the SACN
report provides a decent summary of the evidence to date. Taken
together, it does not make happy reading for the anti-sugar/low-carb
movement. SACN found an association, based on ‘moderate evidence’,
between sugary drinks and type 2 diabetes, but it failed to support any
of the other pet theories of the anti-sugar campaigners. For example, it
found ‘no association’ between sugar and type 2 diabetes, ‘no
association’ between sugar and blood insulin, and ‘no association’
between sugary drinks and childhood obesity. It also found no
association between fructose (the bête noire of the anti-sugar lobby)
and type 2 diabetes. As for the low-carb diet, SACN found ‘no
association between total carbohydrate intake and body mass index or
body fatness’, nor with type 2 diabetes or cardiovascular disease. By
contrast, it found ‘some evidence that an energy restricted, higher
carbohydrate, lower fat diet may be an effective strategy for reducing
body mass index and body weight.’
You need to reach page 183 to find the only part of the 370-page
report that made the headlines. SACN explained its decision to recommend
reducing sugar consumption to five per cent of daily energy as follows:
‘To quantify the dietary recommendation for sugars, advice from the
Calorie Reduction Expert Group was considered. It was estimated that a
418 kJ/person/day (100kcal/person/day) reduction in energy intake of the
population would address energy imbalance and lead to a moderate degree
of weight loss in the majority of individuals (Calorie Reduction Expert
Group, 2011) … To achieve an average reduction in energy intakes of 418
kJ (100kcal/person/day) using this estimated effect size, intake of
free sugars would need to be reduced by approximately five per cent of
total dietary energy (418kJ/78kJ= 5.4) … A five percentage point
reduction in energy from the current dietary recommendation for sugars
would mean that the population average of free sugars should not exceed
five per cent of total dietary energy.’
In other words, the average person consumes too many calories and if
sugar consumption was reduced from 10 per cent of energy to five per
cent of energy, people would eat 100 fewer calories (unless, of course,
they compensated by eating more calories from other sources). This is
the sole justification in the SACN report for changing the guidance on
sugar. The mathematics is correct – 100 calories is roughly five per
cent of an adult’s recommended intake. The logic is not wrong, it is
merely trivial. If the aim of dietary advice is to get people to eat 100
fewer calories a day, similar edicts could be announced about any
ingredient or food. Telling people to eat 25 fewer grammes of cheese a
day would serve exactly the same purpose, but it would not tell us how
much cheese it is safe to eat.
There is no difference whatsoever between saying ‘eat 100 fewer
calories’ and ‘reduce your sugar consumption from 14 teaspoons a day to 7
teaspoons’. The latter, which has now been enshrined in official
guidance, is merely one way of achieving the former. It is doubtful that
even one person in 100 who saw last week’s headlines realises this. It
is much more likely that they think scientists have found new evidence
showing that consuming more than seven teaspoons a day is inherently
dangerous, even toxic.
The clear implication from the new daily ‘allowance’ is that it
represents the upper limit of a risk threshold, above which it is
dangerous to stray. This is not what the SACN report says, and it is not
their justification for changing their guidance, but it will be
portrayed as the ‘safe limit’ by pressure groups forever more.
No comments:
Post a Comment